#include <bits/stdc++.h>
using namespace std;
const int MAX = 2e5+5;

int is_cycle[MAX], cycle[MAX], line[MAX];
int count_cycle, count_line, pos_cycle[MAX], sz_cycle[MAX];
int color[MAX], up[MAX][32];
vector<int> order;
int n, q;

void dfs(int u) {
    order.push_back(u);
    color[u] = 1;
    if (color[up[u][0]] == 1) {
        int to = order.size();
        int cnt = 0;
        do {
            ++cnt;
            --to;
            is_cycle[order[to]] = true;
            cycle[order[to]] = count_cycle;
        } while (to >= 0 and order[to] != up[u][0]);
        to = order.size()-cnt;
        for (int i = to; i < (int)order.size(); ++i) {
            pos_cycle[order[i]] = i-to;
        }
        sz_cycle[count_cycle] = cnt;
        ++count_cycle;
    } else if (color[up[u][0]] == 0) {
        dfs(up[u][0]);
    }
    if (!is_cycle[u]) {
        if (is_cycle[up[u][0]] == 1) {
            line[u] = count_line++;
        } else {
            line[u] = line[up[u][0]];
        }
    }
    color[u] = 2;
    order.pop_back();
}

void same_cycle(int a, int b, int dd=0) {
    if (cycle[a] != cycle[b]) {
        cout << "-1\n";
    } else {
        cout << dd+(pos_cycle[b] - pos_cycle[a] + sz_cycle[cycle[a]]) % sz_cycle[cycle[a]] << '\n';
    }
}

int dist(int node) {
    int dd = 0;
    for (int k = 30; k >= 0; --k) {
        if (!is_cycle[up[node][k]]) {
            node = up[node][k];
            dd += (1 << k);
        }
    }
    node = up[node][0];
    return dd + 1;
}

int main() {
    ios_base::sync_with_stdio(0), cin.tie(0);
    cin >> n >> q;
    memset(up, -1, sizeof up);
    memset(line, -1, sizeof line);
    memset(cycle, -1, sizeof cycle);
    memset(pos_cycle, -1, sizeof pos_cycle);
    for (int i = 0, a; i < n; ++i) {
        cin >> a, --a;
        up[i][0] = a;
    }
    for (int k = 1; k < 31; ++k) {
        for (int i = 0; i < n; ++i) {
            if (~up[i][k-1]) up[i][k] = up[up[i][k-1]][k-1];
        }
    }
    for (int i = 0; i < n; ++i) {
        if (color[i] == 0) {
            dfs(i);
        }
    }
    int a, b;
    while (q--) {
        cin >> a >> b, --a, --b;
        if (is_cycle[a] and is_cycle[b]) {
            same_cycle(a, b);
        } else if (is_cycle[a]) {
            cout << "-1\n";
        } else if (is_cycle[b]) {
            int ans = 0;
            for (int k = 30; k >= 0; --k) {
                if (!is_cycle[up[a][k]]) {
                    a = up[a][k];
                    ans += (1 << k);
                }
            }
            a = up[a][0];
            same_cycle(a, b, ans+1);
        } else {
            if (line[a] != line[b]) {
                cout << "-1\n";
            } else {
                int da = dist(a);
                int db = dist(b);
                if (db >= da) {
                    if (a != b) {
                        cout << "-1\n";
                    } else {
                        cout << "0\n";
                    }
                } else {
                    int diff = da-db;
                    int ans = 0;
                    for (int k = 30; k >= 0; --k) {
                        if (diff >= (1 << k)) {
                            a = up[a][k];
                            diff -= (1 << k);
                            ans += (1 << k);
                        }
                    }
                    if (a != b) {
                        cout << "-1\n";
                    } else {
                        cout << ans << '\n';
                    }
                }
            }
        }
    }
}